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【Android】使用网络技术——WebView的用法、http协议、OKHttp、解析XML、JSON格式数据笔记整理

WebView的用法

新建一个WebView项目

修改activity_main中的代码：

<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/main"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"><WebViewandroid:id="@+id/web_view"android:layout_width="match_parent"android:layout_height="match_parent"/></LinearLayout>

我们在布局文件中用到了新的控件：WebView，用来显示网页

下来修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivity{@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);WebView webView =(WebView)findViewById(R.id.web_view);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setWebChromeClient(newWebChromeClient());
        webView.loadUrl("https://www.csdn.net/");}}

最后加入网络申请权限就可以了：

<uses-permissionandroid:name="android.permission.INTERNET"/>

使用http协议：

新建NetworkTest项目

修改activity_main中的代码：

<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/main"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"><Buttonandroid:id="@+id/send_request"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="Send Request"/><ScrollViewandroid:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/request_text"android:layout_width="match_parent"android:layout_height="wrap_content"/></ScrollView></LinearLayout>

修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{// 用于显示HTTP请求结果的TextViewTextView responseText;@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 获取发送请求按钮的引用Button sendRequest =(Button)findViewById(R.id.send_request);// 获取显示响应结果的TextView的引用
        responseText =(TextView)findViewById(R.id.request_text);// 为按钮设置点击监听器
        sendRequest.setOnClickListener(this);}@OverridepublicvoidonClick(View v){// 检查点击事件是否来自发送请求按钮if(v.getId()==R.id.send_request){// 发送HTTP请求sendRequestWithHttpURLConnection();}}// 使用HttpURLConnection发送HTTP请求privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{// 创建URL对象URL url =newURL("https://www.csdn.net/");// 打开HttpURLConnection
                    connection =(HttpURLConnection) url.openConnection();// 设置请求方法为GET
                    connection.setRequestMethod("GET");// 设置连接超时时间和读取超时时间
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);// 获取服务器响应的输入流InputStream in = connection.getInputStream();// 使用BufferedReader读取输入流
                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}// 显示服务器响应showResponse(response.toString());}catch(Exception e){
                    e.printStackTrace();}finally{// 关闭BufferedReaderif(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}// 断开HttpURLConnection连接if(connection !=null){
                        connection.disconnect();}}}}).start();}// 在UI线程上显示服务器响应privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

最后还需要申请一下网络权限：

<uses-permissionandroid:name="android.permission.INTERNET"/>

如果想要提交数据给服务器可以进行如下修改：

connection.setRequestMethod("POST");DataOutputStream out =newDataOutputStream(connection.getOutputStream());
out.writeBytes("username=admin&password=123456");

注意每条数据都要以键值对的形式存在，数据与数据之间用 

&

分隔开

使用OKHttp

修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{// 用于显示网络请求响应的TextViewTextView responseText;@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 绑定按钮和TextViewButton sendRequest =(Button)findViewById(R.id.send_request);
        responseText =(TextView)findViewById(R.id.request_text);// 为按钮设置点击监听器
        sendRequest.setOnClickListener(this);}@OverridepublicvoidonClick(View v){if(v.getId()==R.id.send_request){// 使用OkHttp发送网络请求sendRequestWithOkHttp();}}// 使用OkHttp发送网络请求的方法privatevoidsendRequestWithOkHttp(){newThread(newRunnable(){@Overridepublicvoidrun(){try{OkHttpClient client =newOkHttpClient();Request request =newRequest.Builder().url("https://www.csdn.net/").build();Response response = client.newCall(request).execute();String responseData = response.body().string();showResponse(responseData);}catch(Exception e){
                    e.printStackTrace();}}}).start();}// 使用HttpURLConnection发送网络请求的方法privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{URL url =newURL("https://www.csdn.net/");
                    connection =(HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);InputStream in = connection.getInputStream();

                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}showResponse(response.toString());}catch(Exception e){
                    e.printStackTrace();}finally{// 关闭资源if(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}if(connection !=null){
                        connection.disconnect();}}}}).start();}// 在UI线程中显示网络请求的响应数据privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

解析XML格式数据

先下载Apache服务器Welcome! - The Apache HTTP Server Project

下载安装后在根目录下的htdocs目录下，新建名为get_data.xml文件：

<apps><app><id>1</id><name>Google Maps</name><version>1.0</version></app><app><id>2</id><name>Chrome</name><version>2.1</version></app><app><id>3</id><name>Google Play</name><version>2.3</version></app></apps>

访问的内容为：

image-20240806160908355

Pull解析

修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{TextView responseText;@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button sendRequest =(Button)findViewById(R.id.send_request);
        responseText =(TextView)findViewById(R.id.request_text);
        sendRequest.setOnClickListener(this);}@OverridepublicvoidonClick(View v){if(v.getId()==R.id.send_request){sendRequestWithOkHttp();}}privatevoidsendRequestWithOkHttp(){newThread(newRunnable(){@Overridepublicvoidrun(){try{OkHttpClient client =newOkHttpClient();Request request =newRequest.Builder().url("https://10.0.2.2/get_data.xml").build();Response response = client.newCall(request).execute();String responseData = response.body().string();parseXmlWithPull(responseData);}catch(Exception e){
                    e.printStackTrace();}}}).start();}privatevoidparseXmlWithPull(String xmlData){try{XmlPullParserFactory factory =XmlPullParserFactory.newInstance();XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(newStringReader(xmlData));int eventType = xmlPullParser.getEventType();String id ="";String name ="";String version ="";while(eventType !=XmlPullParser.END_DOCUMENT){String nodeName = xmlPullParser.getName();switch(eventType){caseXmlPullParser.START_TAG:if("id".equals(nodeName)){
                            id = xmlPullParser.nextText();}elseif("name".equals(nodeName)){
                            name = xmlPullParser.nextText();}elseif("version".equals(nodeName)){
                            version = xmlPullParser.nextText();}break;caseXmlPullParser.END_TAG:if("app".equals(nodeName)){Log.d("MainActivity","id is "+ id);Log.d("MainActivity","name is "+ name);Log.d("MainActivity","version is "+ version);}break;default:break;}
                eventType = xmlPullParser.next();}}catch(Exception e){
            e.printStackTrace();}}privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{URL url =newURL("https://www.csdn.net/");
                    connection =(HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);InputStream in = connection.getInputStream();

                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}showResponse(response.toString());}catch(Exception e){
                    e.printStackTrace();}finally{if(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}if(connection !=null){
                        connection.disconnect();}}}}).start();}privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

但是开始运行后我们并没有成功解析数据

本人遇到的问题是网络安全策略的限制被禁止。默认情况下，从Android 9（API级别28）开始，应用程序不允许进行明文HTTP流量，所以需要修改应用的网络安全配置来允许明文流量。

创建网络安全配置文件：

在

res/xml

目录下创建一个名为

network_security_config.xml

的文件，并添加以下内容：

<?xml version="1.0" encoding="utf-8"?><network-security-config><domain-configcleartextTrafficPermitted="true"><domainincludeSubdomains="true">192.168.1.75</domain><!-- 替换为您的局域网IP地址 --></domain-config></network-security-config>

引用网络安全配置文件

AndroidManifest.xml

中引用这个网络安全配置文件：

<applicationandroid:networkSecurityConfig="@xml/network_security_config"...>
    ...
</application>

修改MainActivity：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{privatestaticfinalStringTAG="MainActivity";TextView responseText;@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button sendRequest =findViewById(R.id.send_request);
        responseText =findViewById(R.id.request_text);
        sendRequest.setOnClickListener(this);}@OverridepublicvoidonClick(View v){if(v.getId()==R.id.send_request){sendRequestWithOkHttp();}}privatevoidsendRequestWithOkHttp(){newThread(newRunnable(){@Overridepublicvoidrun(){try{OkHttpClient client =newOkHttpClient();// 使用电脑的局域网IP地址Request request =newRequest.Builder().url("http://192.168.1.75/get_data.xml").build();Response response = client.newCall(request).execute();String responseData = response.body().string();Log.d(TAG,"Response data: "+ responseData);parseXmlWithPull(responseData);}catch(Exception e){Log.e(TAG,"Request failed", e);}}}).start();}privatevoidparseXmlWithPull(String xmlData){try{XmlPullParserFactory factory =XmlPullParserFactory.newInstance();XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(newStringReader(xmlData));int eventType = xmlPullParser.getEventType();String id ="";String name ="";String version ="";while(eventType !=XmlPullParser.END_DOCUMENT){String nodeName = xmlPullParser.getName();switch(eventType){caseXmlPullParser.START_TAG:if("id".equals(nodeName)){
                            id = xmlPullParser.nextText();}elseif("name".equals(nodeName)){
                            name = xmlPullParser.nextText();}elseif("version".equals(nodeName)){
                            version = xmlPullParser.nextText();}break;caseXmlPullParser.END_TAG:if("app".equals(nodeName)){Log.i(TAG,"id is "+ id);Log.i(TAG,"name is "+ name);Log.i(TAG,"version is "+ version);}break;default:break;}
                eventType = xmlPullParser.next();}}catch(Exception e){Log.e(TAG,"XML parsing failed", e);}}privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{URL url =newURL("http://192.168.1.75/get_data.xml"); 
                    connection =(HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);InputStream in = connection.getInputStream();

                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}showResponse(response.toString());}catch(Exception e){Log.e(TAG,"Request failed", e);}finally{if(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}if(connection !=null){
                        connection.disconnect();}}}}).start();}privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

解析JSON格式数据

相比于XML，JSON的主要优势在于它的体积更小，在网络传输时可以更省流量

但是缺点在于它的语义性较差

首先在Apache目录下的htdocs目录中新建一个get_data.json文件，加入以下内容：

[{"id":"5","version":"5.5","name":"Clash of Clans"},{"id":"6","version":"7.0","name":"Boom Beach"},{"id":"7","version":"3.5","name":"Clash Royale"}]

在浏览器打开为：

image-20240806201033387

下面就可以开始解析数据了：

使用JSONObject

修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{privatestaticfinalStringTAG="MainActivity";TextView responseText;@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button sendRequest =findViewById(R.id.send_request);
        responseText =findViewById(R.id.request_text);
        sendRequest.setOnClickListener(this);}@OverridepublicvoidonClick(View v){if(v.getId()==R.id.send_request){sendRequestWithOkHttp();}}privatevoidsendRequestWithOkHttp(){newThread(newRunnable(){@Overridepublicvoidrun(){try{OkHttpClient client =newOkHttpClient();Request request =newRequest.Builder().url("http://192.168.1.75/get_data.json")// 确认返回的是JSON数据.build();Response response = client.newCall(request).execute();String responseData = response.body().string();Log.d(TAG,"Response Data: "+ responseData);parseJSONWithJSONObject(responseData);}catch(Exception e){Log.e(TAG,"Request failed", e);}}}).start();}privatevoidparseJSONWithJSONObject(String jsonData){try{JSONArray jsonArray =newJSONArray(jsonData);for(int i =0; i < jsonArray.length(); i++){JSONObject jsonObject = jsonArray.getJSONObject(i);String id = jsonObject.getString("id");String name = jsonObject.getString("name");String version = jsonObject.getString("version");Log.d(TAG,"id is "+ id);Log.d(TAG,"name is "+ name);Log.d(TAG,"version is "+ version);}}catch(JSONException e){Log.e(TAG,"JSON parsing failed", e);}}privatevoidparseXmlWithPull(String xmlData){try{XmlPullParserFactory factory =XmlPullParserFactory.newInstance();XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(newStringReader(xmlData));int eventType = xmlPullParser.getEventType();String id ="";String name ="";String version ="";while(eventType !=XmlPullParser.END_DOCUMENT){String nodeName = xmlPullParser.getName();switch(eventType){caseXmlPullParser.START_TAG:if("id".equals(nodeName)){
                            id = xmlPullParser.nextText();}elseif("name".equals(nodeName)){
                            name = xmlPullParser.nextText();}elseif("version".equals(nodeName)){
                            version = xmlPullParser.nextText();}break;caseXmlPullParser.END_TAG:if("app".equals(nodeName)){Log.i(TAG,"id is "+ id);Log.i(TAG,"name is "+ name);Log.i(TAG,"version is "+ version);}break;default:break;}
                eventType = xmlPullParser.next();}}catch(Exception e){Log.e(TAG,"XML parsing failed", e);}}privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{URL url =newURL("http://192.168.1.75/get_data.json");// 确认返回的是JSON数据
                    connection =(HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);InputStream in = connection.getInputStream();

                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}showResponse(response.toString());}catch(Exception e){Log.e(TAG,"Request failed", e);}finally{if(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}if(connection !=null){
                        connection.disconnect();}}}}).start();}privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

使用GSON

要想使用GSON，首先需要添加依赖库：

implementation("com.google.code.gson:gson:2.7")

新建App类：

packagecom.example.networktest;publicclassApp{privateString id;privateString name;privateString version;publicStringgetId(){return id;}publicvoidsetId(String id){this.id = id;}publicStringgetName(){return name;}publicvoidsetName(String name){this.name = name;}publicStringgetVersion(){return version;}publicvoidsetVersion(String version){this.version = version;}}

修改MainActivity中的代码：

publicclassMainActivityextendsAppCompatActivityimplementsView.OnClickListener{privatestaticfinalStringTAG="MainActivity";// 日志标签TextView responseText;// 用于显示响应数据的TextView@OverrideprotectedvoidonCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 设置活动布局Button sendRequest =findViewById(R.id.send_request);// 获取发送请求按钮
        responseText =findViewById(R.id.request_text);// 获取用于显示响应的TextView
        sendRequest.setOnClickListener(this);// 为按钮设置点击事件监听器}@OverridepublicvoidonClick(View v){if(v.getId()==R.id.send_request){// 检查点击的视图ID是否为发送请求按钮sendRequestWithOkHttp();// 调用方法发送HTTP请求}}// 使用OkHttp发送HTTP请求privatevoidsendRequestWithOkHttp(){newThread(newRunnable(){@Overridepublicvoidrun(){try{OkHttpClient client =newOkHttpClient();Request request =newRequest.Builder().url("http://192.168.1.75/get_data.json")// 请求URL.build();Response response = client.newCall(request).execute();// 执行请求String responseData = response.body().string();// 获取响应数据parseJSONWithGSON(responseData);// 解析JSON数据}catch(Exception e){Log.e(TAG,"Request failed", e);// 记录请求失败的日志}}}).start();}// 使用GSON解析JSON数据privatevoidparseJSONWithGSON(String jsonData){Gson gson =newGson();List<App> appList = gson.fromJson(jsonData,newTypeToken<List<App>>(){}.getType());// 将JSON数据转换为App对象列表for(App app : appList){Log.d("MainActivity","id is "+ app.getId());Log.d("MainActivity","name is "+ app.getName());Log.d("MainActivity","version is "+ app.getVersion());}}// 使用JSONObject解析JSON数据privatevoidparseJSONWithJSONObject(String jsonData){try{JSONArray jsonArray =newJSONArray(jsonData);// 创建JSON数组for(int i =0; i < jsonArray.length(); i++){JSONObject jsonObject = jsonArray.getJSONObject(i);String id = jsonObject.getString("id");String name = jsonObject.getString("name");String version = jsonObject.getString("version");Log.d(TAG,"id is "+ id);Log.d(TAG,"name is "+ name);Log.d(TAG,"version is "+ version);}}catch(JSONException e){Log.e(TAG,"JSON parsing failed", e);// 记录JSON解析失败的日志}}// 使用Pull解析XML数据privatevoidparseXmlWithPull(String xmlData){try{XmlPullParserFactory factory =XmlPullParserFactory.newInstance();XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(newStringReader(xmlData));int eventType = xmlPullParser.getEventType();String id ="";String name ="";String version ="";while(eventType !=XmlPullParser.END_DOCUMENT){String nodeName = xmlPullParser.getName();switch(eventType){caseXmlPullParser.START_TAG:if("id".equals(nodeName)){
                            id = xmlPullParser.nextText();}elseif("name".equals(nodeName)){
                            name = xmlPullParser.nextText();}elseif("version".equals(nodeName)){
                            version = xmlPullParser.nextText();}break;caseXmlPullParser.END_TAG:if("app".equals(nodeName)){Log.i(TAG,"id is "+ id);Log.i(TAG,"name is "+ name);Log.i(TAG,"version is "+ version);}break;default:break;}
                eventType = xmlPullParser.next();}}catch(Exception e){Log.e(TAG,"XML parsing failed", e);// 记录XML解析失败的日志}}// 使用HttpURLConnection发送HTTP请求privatevoidsendRequestWithHttpURLConnection(){newThread(newRunnable(){@Overridepublicvoidrun(){HttpURLConnection connection =null;BufferedReader reader =null;try{URL url =newURL("http://192.168.1.75/get_data.json");// 请求URL
                    connection =(HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);InputStream in = connection.getInputStream();

                    reader =newBufferedReader(newInputStreamReader(in));StringBuilder response =newStringBuilder();String line;while((line = reader.readLine())!=null){
                        response.append(line);}showResponse(response.toString());// 显示响应数据}catch(Exception e){Log.e(TAG,"Request failed", e);// 记录请求失败的日志}finally{if(reader !=null){try{
                            reader.close();}catch(IOException e){
                            e.printStackTrace();}}if(connection !=null){
                        connection.disconnect();}}}}).start();}// 在主线程上显示响应数据privatevoidshowResponse(finalString response){runOnUiThread(newRunnable(){@Overridepublicvoidrun(){
                responseText.setText(response);}});}}

打印结果如图所示：

image-20240807100732949

已经到底啦！！

标签： android http okhttp
本文转载自: https://blog.csdn.net/2301_79977698/article/details/140981890
版权归原作者 xiaoduyyy 所有， 如有侵权，请联系我们删除。
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